A non-ionic glucomannan from the seeds of an indigenous medicinal plant:: Bryonia lacinosa

Extraction of defatted and decolorized seeds of Bryonia lacinosa with 1% aqueous acetic acid yielded a polysaccharide material, having D-glucose and D-mannose in the molar ratio of 1.00:1.01. Hydrolysis of the fully methylated seed gum furnished 2,3,4,6-tetra-O-methyl-D-glucose and 2,3-di-O-methyl-D-mannose in equimolar ratio. Partial hydrolysis of the polysaccharide furnished three oligosaccharides namely; epigentiobiose, mannobiose, and mannotriose along with the component monosaccharides. Periodate oxidation indicated about 49.75% of the end groups in the seed gum, which was in close agreement with the end groups calculated from methylation analysis, i.e. 49.55%. On the basis of the above results, a structure for the repeating unit of the polysaccharide, has been proposed in which the main chain consists of P (1 -> 4) linked mannopyranosyl units to which D-glucopyranosyl units are linked by a (1 -> 6) linkages. (c) 2006 Elsevier Ltd. All rights reserved.